Many food products, such as those mentioned above, are individually packaged for sale on grocery store shelves. The packages have a finite volume typically on the order of 250 cubic inches and a finite weight, typically on the order of one-half to three pounds. For obvious reasons, manufacturers would like to maintain the weight of the product as closely as possible to the weight designated on the outside of the individual package or box. Underweight products violate federal packaging and marketing standards. At the same time, manufacturers cannot guarantee the minimum weight of food simply by providing an excess volume of food product. Boxes in which the food product is placed have a finite volume, and an excess volume may cause the boxes to distend outwardly, tearing them, or making it difficult or impossible to package them into cartons or containers for shipping.
Further complicating the processes of appropriately portioning the food product is the fact that the food product manufacturing process itself may cause the relationship between volume and weight to vary widely. The relationship between volume and weight is called the “bulk density”. Bulk density is expressed as units of weight per units of volume. Typically, it is expressed as ounces per cubic inch or grams per cubic centimeter, although these units of measure are not mandatory. If the bulk density of a food product increases dramatically as food processing equipment drifts from its nominal and preferred position, a unit of weight of the food product will take up a considerably smaller volume. While this is enough to meet federal and state packaging standards, since the weight is held constant, consumers are often upset because the large package they have only appears to be half full. Even though the weight is correct, the reduced volume leaves the consumer feeling angry and frustrated. Similarly, if the bulk density of the food product drops dramatically, a given weight of the product will take up a considerably larger volume. When this happens, if the portioning process for each of the packages is based solely upon weight, the portions will increase in volume and may jam the packaging machinery causing it to fail. This requires shutting down the packaging machinery and cleaning it out. Any shut-down of the food processing line imposes a significant cost on the food manufacturer. What is needed, therefore is a system and process for feeding back a signal indicative of the bulk density of the product being portioned and packaged to the food manufacturing process so that it can be adjusted on the fly and the proper bulk density, weight, and volume of each individually wrapped portion can be properly maintained. It is an object of this invention to provide such a system and process.